Quiz 6: 1 Flashcards
What are the Ottawa knee rules?
- Age over 55
- Isolated tenderness of patella
- Tenderness at fibular head
- Inability to flex knee past 90˚
- Inability to bear weight both immediately and in the ER (4 steps)
*Do #5 if all others are negative
If the Ottawa knee rules are positive, what do these rules indicate?
Radiograph needed
What are concomitant injuries seen with grade III MCL sprains?
- Medial meniscus tear
- Articular cartilage injury
- Avulsion fx
How much medial restraint does the MCL provide at 0˚ of knee extension?
57%
What other structures help provide medial restraint at 0˚ of knee extension?
- ACL
- PCL
- ant/mid capsule
- posterior capsule
Why do you perform testing at both 0˚ and 30˚ for the MCL?
To isolate the MCL from other structures
MCL makes up 78% of the medial restraints at 30˚ vs 57% at 0˚
Most common MCL sprain MOI
Traumatic valgus force
Compare ACL MOI to MCL MOI
- ACL is non-contact (no outside force)
- MCL generally involved contact
What is the cluster of s/s for an MCL tear?
- Pt describes MOI
- Pt may describe “tearing” sensation
- Pain
- Pain with palpation over MCL
Differentiate between sprain and strain
- Sprain: noncontractile tissue
- Strain: contractile tissue
What is the AMA classification of knee instability testing and what type of laxity do you have with each?
- Grade 1: mild sprain, no laxity
- Grade 2: moderate sprain (1+, 2+)
- Grade 3: severe sprain (3+)
Grade 1 MCL sprain: laxity
None
Grade 2 MCL sprain: laxity
Moderate
1+ = 1-5 mm more laxity than uninvolved side
2+ = 6-10 mm more laxity
Grade 3 MCL sprain: laxity
Severe
3+ = more than 10 mm more laxity
What special test can you do to test the MCL?
valgus stress test
What is the first thing you should do to start the valgus stress test?
Go to varus position to close the joint
Why do you need to move into varus position prior to valgus stress test?
To approximate the joint so you can palpate and kinesthetically feel it
What should a positive valgus stress test in a younger person make you think?
Femoral epiphyseal plate injury
If an epiphyseal plate injury is present, what is happening?
The ligament is stronger than the physis
What is an additional comorbidity with an MCL valgus stress injury?
PF subluxation
